Control apparatus for internalcombustion engines



June 1, 1948. D. E. LIPFERT 2,442,421

CONTROL APPARATUS FOR INTERNAL-COMBUSTION ENGINES Filed Sept. 4, 1946 TO[RAIN INYENTOR ZYIINHLDHLJPPERT AGENT Patented June 1 1948 coN'raoLAPPARATUS FOR INTERNAL- COMBUSTION ENGINES Donald E. Lipfert, Meriden,Conn., assignor, by

mesne assignments, to

Niles-Bement-Pond Company, West Hartford, Conn, a corporation of NewJersey Application September 4, 1946, Serial No. 694,695

5 Claims. 1

The present invention relates to control apparatus for internalcombustion engines, and particularly to control apparatus for regulatingthe delivery of engine driven fuel injection pumps.

An object of this present invention is to provide means for positivelypositioning the delivery control mechanism of an injector pump inaccordance with a variable controlling condition.

Another object is to provide means for positioning the delivery controlmechanism of fuel injector pumps, wherein the power for positioning thedelivery control is taken directly from the engine.

Other objects and advantages of my invention become apparent from aconsideration of the appended specification, claims and drawing, inwhich The single figure represents, somewhat diagrammatically, a fuelsupply system for an internal combustion engine embodying the principlesof my invention.

Referring now to the drawing, there is shown an air conduit in, thruwhich combustion air for an engine flows from an entrance [2, past aventuri l4 and a throttle I6, to a discharge outlet it. The outlet i8may deliver air either directly to the engine intake manifold or to theintake of the supercharger. In some cases, a supercharger may beprovided anterior to the entrance l2.

The venturi i4 follows the well-known laws governing the characteristicsof such devices. Therefore there is established between the entrance i2and the throat of venturi I4 a differential of air pressures, which is ameasure of the velocity of the air flowing thru conduit II).

This difference of air pressures sets up a flow of air thru a secondaryair passage which may be traced from an impact tube 20 opening intoentrance 12, thru a conduit 22, a restriction 24, a conduit 26, past avalve 28 into a chamber 30, and thru a conduit 32 to the throat ofventuri M.

The valve 28 is positioned by a sealed flexible bellows 34, mounted inthe chamber 30. The bellows 34 proper contains a fluid having anappreciable coeflicient of thermal expansion, so that the position ofvalve 28 varies with both the pres- I sure and temperature of the air inthe chamber 30. By positioning the valve 28 in accordance with thepressure and temperature of the air, it may be made to regulate thepressure drop across restriction 24 substantially in accordance with themass of air flowing thru air passage l0 per unit time. This manner ofpressure and temperature compensation is more fully described in thepat- 2 ent to Milton E. Chandler, No. 2,393,144, dated January 15, 1946.

The pressure drop established across restriction 24 is communicated thruconduits 36 and 38 to chambers 40 and 42, respectively. The chambers 40and 42 are separated by a flexible diaphragm 44 and are located in apressure meter generally indicated as 46.

It may be seen that the force acting downwardly on the diaphragm 44 dueto the difference in pressure in chambers 40 and 42 is a measure of therate of flow of air to the engine". Attached to the center of diaphragm44 is a valve stem 48,

which extends thru another diaphragm 50 and carries a valve 52 on theopposite side of diaphragm 50. The valve 52 co-operates with an annularseat 54, and regulates the flow between an inlet chamber 56 outside theseat 54 and an outlet chamber 58 inside the seat 54. Fuel under phragm56 so that the valve 52 opens until its opening movement has relievedthe pressure in inlet chamber 56 sufiiciently so that the forces on thediaphragms are again balanced. It may therefore be seen that thepressure meter 46 operates to maintain a, pressure in chamber 56 whichis a measure of the rate of flow of air to the engine.

Fuel for the engine comes from a tank or other source (not shown) andflows thru a conduit 62, an engine driven pump 64, a mixture controlunit 66, a jet system 68, and a conduit 10 to the injector pumps, one ofwhich is illustrated at 12.

The pump 64 is provided with a pressure relief valve 14 which maintainsits discharge pressure at a susbtantially constant value.

The mixture control unit 66 includes a disc valve 69 fixed on a shaft16, which is manually rotatable by means not shown. When the disc valve69 is in the full-line position shown in the drawing, fuel can flow fromthe mixture control unit to the jet system only thru a conduit 18. Whenthe valve 69 is moved to the dotted line position shown in the drawing,then fuel can flow to a closed position by a the valve 40 is known asthe "lean" position of the mixture control. and the dotted line positionis termed the "rich" position. The valve may also be moved to a positionwherein it cuts off all the flow of fuel to the jet system 00. Thislatter position is known as the "cut-off" podtion.

Fuel entering the jet system 03 thru conduit 13 passes thru a fixedrestriction or Jet 02, or a restriction 34 controlled by a valve 00,biased ing the jet system thru conduit 00 passes thru a fixedrestriction O0. 7 Fuel passing thru restrictions 04 and 00 also passesthru another fixed restriction 02.

The injector pump appearing at 12 is of conventional form, and includesa plunger 04 reciprocated by a cam 80, driven by the engine. The plungercarries a pinion 00, which mates with a rack I00. By reciprocating therack III the plunger may be rotated on its axis. The plunger is providedwith a helical groove co-operating with the inlet port thru which fuelis admitted to the cylinder ahead of the plunger. By rotation of theplunger, the point in the plunger travel at which the inlet port isclosed and pumping begins may be varied. In this manner the quantity offuel delivered per stroke of the plunger is controlled.

The rack I00 is positioned by a pinion gear I02 on a shaft I04. Theshaft I04 is in turn driven by a gear I03 which mates with a gear I00 ona shaft H0. The shaft IIII carries a friction clutch member II2, whichis springbiased into engagement with another friction clutch member H4.The clutch member H4 is coupled by suitable mechanism with a shaft II!which carries on a suitable frame IIG a pair of opposed spaced bevelgears H3 and I20. The right end of shaft I I5, as it appears in thedrawing, turns in a bearing I22 carried by a rod I23.

A bevel gear I2I lies between the opposed bevel gears H8 and I and isfixed on a shaft lit driven by the engine. The gear I2I is normallyspaced from both of the gears Ill and I20.

The rod I23 is attached to the free ends of a pair of opposed bellowsI24 and I30. The bellows I24 separates a pair of expansible chambers I23and I28 The bellows I30 separates a pair of expansible chambers I32 andI34.

The chamber I26'is connected thru a conduit I to the conduit 22 leadingto the impact tube 20. The chamber I28 is connected thru a conduit I42to the fuel conduit 10 on the downstream side of the jet system 68. Thechamber I32 is connected thru conduit I44 to the fuel line on theupstream side of the jet system. The chamber I34 is connected to theconduit 60, wherein, as previously described, the pressure is maintainedproportional to the'rate of flow of air to the engine. The conduit-30recelves its supply of fuel from conduit I44 thru restriction I50.

The conduit I40 provides a vent for chamber I26. It may be seen that thepressure in chamber I34 acts to the left on the bellows I30 andtherefore a force is applied to the left on rod I23 which is a measureof the rate of flow of air to the engine. At the same time the fuelpressure on the upstream side of the jet system is communicated tochamber I32, where it acts to the right on bellows I30. The fuelpressure.

downstream from the jet system is communicated to chamber I28 where itacts to the left on belspring 00. Fuel enterlows I24, For a given areaof a jet system open to the flow of fuel, the pressure drop across it isa measure of the rate of flow of fuel therethru. Hence it may be seenthat the net force acting to the right on hearing I22 due to thediiference in the pressure in chambers I32 and I23 is a measure of therate of flow of fuel to the engine. Therefore the valve I22 ispositioned in accordance with the balance of two forces. oneproportional to the rate of flow of fuel to the engine and the otherproportional to the rate of flow of air to the engine.

The pressure in chamber I20 is small as compared to the pressures in theother three chambers I23, I32 and I34. Furthermore, it is substantiallyconstant, as compared to the variations in pressure in the other threechambers. In addition, any changes in that pressure act on rod I22 inthe proper direction to correct the fuel flow for variations in thedensity of the entering air.

When the air and fuel flows are balanced, the frame H6 is positioned bythe two bellows I30 and I24 as shown in the drawing, so that the shaftH5 is then not driven by shaft 9.

If the air flow increases, indicating a need of increased fuel flow itthe same fuel-air ratio is to be maintained, then the increased pressurein chamber I34 moves rod I23 to the left, carrying bevel gear I20 intoengagement with gear I2I. This causes rotation of the shaft H5 in adirection to drive rack I00 in a fuel pump delivery increasingdirection. The rack I00 continues to be driven in that direction untilthe fuel pressure differential acting on the bellows I30 and I24 hasincreased and moved the rod I23 to disengage the gears I20 and I2I. Atthat' time the air and fuel flows will again be balanced.

In a similar manner, as the air flow decreases, the rod I23 moves to theright, moving gear II8 to engagement with gear I2I. The shaft H5 is thendriven in the opposite direction, so as to move the rack I00 to reducethe pump delivery.

The bevel gears II8, I20 and I2I are shown by way of example only. Thesegears may be replaced by any equivalent pair of oppositely acting clutchmechanisms,

The friction clutch members H2 and H4 are provided to allow relativemovement of the shafts H0 and H5 when the rack I00 has reached the endof its travel and the gears H8 or I20 remain engaged with gear I2I.

It may, therefore, be seen that I have provided a mechanism forpositioningan injector pump delivery control which is positive in itsaction, since it takes the power directly from the engine. Furthermore,it is rapid In its action, because the shaft I2I is continuouslyrunning.

The terms and expressions which I have employed are used as terms ofdescription and not of limitation, and I have no intention, in the useof such terms and expressions, of excluding any equivalents of thefeatures shown and described or portions thereof, but recognize thatvarious modifications are possible within the scope of the inventionclaimed.

I claim as my invention:

1. Control apparatus for an internal combustion engine, comprisinginjector pump means driven by said engine for delivering fuel to thecylinders of said engine, means for varying the delivery of saidinjector pump means, a power shaft driven by said engine, a controlshaft connected to said delivery varying means for positiming the same,and reversing clutch means for connecting said power shaft to saidcontrol shaft so as to cause operation of said control shaft selectivelyin opposite directions, and means for operating said clutch means.

2. Control apparatus for an internal combustion engine, comprisinginjector pump means driven means for varying the delivery of saidinjector pump means, a. power shaft driven by said engine, a controlshaft connected to said delivery varying means for positioning the same,a pair of selectively operable clutches for connecting said power shaftto said control shaft, one of said clutches being effective to causeoperation of said control shaft in a direction opposite to theothenmeans for measuring the rate of flow of combustion air to saidengine, means for measuring the rate of flow of fuel to said engine,means including both said measuring means for controlling the selectiveoperation of said clutche and a continuously engaged friction clutchassociated with one of by said engine for delivering fuel thereto,

said shafts to permit continued rotation of said power shaft after saiddelivery reached the end of its travel.

3. Control apparatus for an internal combustion engine, comprisinginjector pump means driven by said engine fordelivering fuel thereto,means for varying the delivery of said injector pump means, a powershaft driven by said engine, a control shaft "connected to said deliveryvarying means for positioning the same, a pair of selectively operableclutches for connecting said power shaft to said control shaft, one ofsaid clutches being effective to cause operation of said control shaftin a direction opposite to the other, means varying means has forcontrolling the selective operation of said clutches, and a continuouslyengaged friction clutch associated with one of said shafts to permitcontinued rotation of said power shaft after said delivery varying meanshas reached the end of its travel. Y

' 4. Control apparatus for an internal combustion engine, comprisinginjector pump means driven by said engine for delivering fuel thereto,means forvarying the delivery of said injector pump means, a power shaftdriven by said engine, a control shaft connected to said deliveryvarying means for positioning the same, a pair of selectively operableclutches for connecting said power shaft to said control shaft, one ofsaid clutches being effective to cause operation of said control shaftin a, direction opposite to the other, and

means for controlling the selective operation of said clutches.

5. Control apparatus for an internal combustion engine, comprisinginjector pump means driven by said engine for delivering fuel thereto,means for varying the delivery of said injector pump means, a powershaft driven by said engine, a control shaft connected to said deliveryvarying means for positioning the same, a pair of selectively operableclutches for connecting said power shaft to said control shaft, oneofsaid clutches being effective to cause operation of said control shaftin a. direction opposite to the other, means for measuring the rate offlow of combustion air to said engine, and means including both saidmeasuring means for controlling the selective operatlon of saidclutches.

DONALD E. LIPFERT.

